I've seen lots of 3"-4" dia. vine maple branches growing perfectly horizontal for 30'. Those are the ones I go after. The topside of the branch is the tension side and when you split it, that will also be the side with reflex. In fact, if you split it or rough it to shape, and debark it fresh cut green (something I've done on every camping trip), you need to strap it down or it will turn into a crab bow. No need to clamp in any reflex, it'll make it's own. I prefer to leave the staves for a couple of weeks before doing any splitting or roughing. Then it will still be wet enough to work like green wood and the bark will still come off easy but you wont get as wild a reflex. You'll still get some.